Much current research in infant development is concerned with understanding neurobehavioral organization in the neonate, analyzing adaptive capabilities and identifying variables which affect neonatal behavioral organization and adaptation (32,33,38,41,44). It is now evident that prenatal exposure to PCP or cocaine affects neurobehavioral function neonates and infants (1,2,3,4,5,6.7.8.9.10,16). Data from human and animal studies suggest that the behavioral changes associated with PCP or cocaine exposure in utero may reflect the effects of PCP and cocaine on nervous system function and neurotransmitter activity in the neonate (7,8,9,10,25,28,29,30). PCP and cocaine have been found to block the uptake of norepinephrine, serotonin and dopamine, which can result in the increased motor activity and tone, alternating lethargy, and increased responses to auditory stimuli that have been observed in these babies (26,27,28,29,23). The effects of PCP and cocaine exposure may not be limited to these behavioral changes. Recent evidence suggests that exposure to PCP and cocaine in utero may also result in decreased responsivity to environmental stimuli, impaired sensory capabilities in the neonate, particularly in relation to feeding behavior, and delayed development in the first year of life (8,9,10,16,20). This research is concerned with the specification of the range of effects of PCP or cocaine exposure on neurobehavioral functioning in the human neonate, particularly the assessment of effects on early sensory abilities and sucking behavior. The proposed research is designed to evaluate dearly sensory capabilities in PCP and cocaine exposed infants by assessing taste discrimination in these infants at 24 and 48 ours after birth. Growth parameters (weight gain, head circumference, length) will be monitored throughout the study and developmental assessments will be conducted at 6 months of age. It is hypothesized that PCP and cocaine exposed infants will show depressed sucking behavior, decreased responsivity to taste stimuli and poorer weight gain. It is also hypothesized that taste discrimination skills and growth parameters will be related to developmental outcome at six months of age.